Yo Xing Heyno Augustus Eisner Alexander Weiser Knuckles Jeremijenko-Conley, 18, has what’s believed to be the longest name in New York City.

While Yo, as everyone calls the University of California, San Diego, freshman, stands on one end of the name-length spectrum, his sister — E Nora Harper Jeremijenko-Conley — is on the other. With just one measly character, she has the shortest first name in the Big Apple.

“I always have to introduce myself as ‘E like the letter,’ or else people think it’s Eve,” said the 20-year-old Princeton sophomore. “[E] doesn’t stand for anything, so it doesn’t have a period.”

It all started with E’s premature birth. “She was born two months early. We thought about Early as a name, but we decided we would punt being decisive, and E would be a temporary stand-in for whatever she wanted to choose,” dad Dalton Conley, a sociologist at Princeton, told The Post. “Your name is like your race, or your sex, or your social origins — something you have no control over. We’re saying, ‘Let’s give a kid some control over that.’ ”

Two years later, when he and then-wife Natalie Jeremijenko, an artist and engineer, were expecting again, Conley suggested Xing-Yo “to challenge the ethnic assumptions of a name.” (As an added bonus, the initials XY would mirror the baby boy’s sex chromosomes.) But Jeremijenko was superstitious — and freaked out that Conley had uttered the name aloud. So the couple settled on Yo.

Yo’s original middle names — Augustus Eisner Alexander Weiser — honor relatives and close family friends. But when the boy was 4, his parents decided to add Xing, since they still liked it. They also decided to let the toddler have a say: He requested Heyno, after a frequent and familiar admonition, and Knuckles, after his father’s late dog.

Despite her parents’ intentions, E has no desire to change her name — even though online forms sometimes don’t allow users to input only one letter as a given name.

“My college friends . . . will call me a different thing every day, like Edamame or Eraser,” said E, who is studying anthropology.

Yo admits he took a little while to accept his protracted moniker.

“At one point, he wanted to be called Shawn. At one point he wanted to be called Dragon,” Conley said. “He wanted to be quote-unquote normal.”

“I was in a phase where I wanted to start a band,” explained Yo, who is studying math, economics and data science. “I was thinking, ‘None of the celebrities I know have weird names. If I want to be famous, I need to have a normal-sounding name.’ Which is counterintuitive, because it’s actually what I’ve gotten the most [attention] for.”

Now, even though his name doesn’t fit in an email address or on a credit card, Yo “definitely” likes his name. “Everyone remembers it,” he said, which helps “for job interviews and making new friends . . . I show them my learner’s permit and it blows their minds.”

Still, he plans to be more conservative when naming his future kids.

“I definitely don’t want to give the very standard names, but I don’t want to name them as crazy as Yo, or give them 10 middle names,” said Yo.

E, however, has more ambitious goals.

“I think Felony would make a great name. Placenta or Chlamydia or Diarrhea — I think those would be great if they didn’t mean what they did,” she said. “Zero would be a great name because it’s such a powerful number. It would be nice to name your child Lovely so they feel good.

“Names should be something that feel special,” E added. “Every day, I would take the E train to high school. If I had a bad day I would pretend the train was just for me.”